1. Field of the Invention
This invention relates to a hemostatic surgical instrument. More specifically, this invention relates to a surgical scalpel with guide means to facilitate appropriate placement during formation of an incision, for example between the pericranium and galea of the scalp. The invention also relates to a surgical stapling device with convex outer margin, which device may be combined with the surgical scalpel, allowing placement of parallel rows of staples on either side of an incision with minimal blood loss.
2. Background Information
With standard methods, incisions through the scalp involve a substantial blood loss both at the initiation and at the end of the procedure. In general, the scalp is a very vascular entity with a large plexus of blood vessels within the galeal layer. The standard method for incising the scalp at this time involves making an initial incision with a standard scalpel followed by the placement of hemostatic clips, one form of which is commonly referred to in the art as the Raney clip. Because of the time involved and the profuse bleeding from cranial blood vessels, loss of blood is of major concern in these procedures. See, for example, Ortichochea, A Pneumatic Cranial Tourniquet to Control Haemorrhage During Operations on the Scalp, 30 British J. Plastic Surg., 223-26 (1977); Hammersley, Clips for the Control of Hemorrhage from the Bitemporal Scalp Flap, 41 J. Oral Maxillofac. Surg. 686-87 (1983); Coleman & Rocko, Rapid Control of Hemorrhage of the Scalp in the Patient with Trauma, 166 Surg., Gynecol. & Obstetrics 165-66 (1988); Sakhai, Hemostatic Control of Scalp Incisions, 70 J. Neurosurg. 142 (1989), incorporated herein in their entirety by reference thereto. There is a significant blood loss between initial formation of the incision and placement of the hemostatic clips at the beginning of the case and another period of blood loss between the time the clips are removed and the scalp is closed at the end of the case. This blood loss is frequently in the range of an entire unit of blood.
Several hundred thousand pericranial incisions are done in North America, South America, Japan, and Europe on a yearly basis. The threat of hepatitis and AIDS with blood transfusions is a significant incentive to use any instrument that significantly decreases the need for blood transfusions.
Other surgical instruments encompass surgical stapling units, or surgical stapling units in conjunction with surgical blades, allowing formation of an incision with concurrent placement of surgical staples on either side of the incision. Such instruments are exemplified by Kapitanov et al. U.S. Pat. No. 4,244,372, Green U.S. Pat. No. 4,520,817, Fedotov et al. U.S. Pat. No. 4,596,351, Rothfuss et al. U.S. Pat. No. 4,608,981, and Chow et al. U.S. Pat. No. 4,633,874. However, none of these instruments is readily adaptable to performing incisions on the surfaces of curved tissue substrates, such as the scalp, by providing for a curved stapling unit capable of following complex curvatures in multiple planes. In addition, none of the above instruments specifically provides for guide means to define an interval between specific tissue layers, for example between the galea and pericranium during a scalp incision.
Accordingly, there is a need for an instrument designed to make an incision in a tissue of complex curvature with minimal blood loss and to allow closure prior to removing the hemostatic element. A further need exists for an instrument that will significantly reduce the operating time for surguries involving pericranial incisions in both neurosurgery and plastic surgery, and thus result in a corresponding reduction in blood transfusions and the costs and dangers associated therewith.